In the various mechanical arts there are known a wide range of hand implements comprising an elongated structure having a handle end which is formed to be grasped by a user, and a working end formed to strike an object upon manual swinging of the implement by the user.
For example, the well known carpenter's hammer comprising a forged steel head mounted on one end of an elongated wooden handle such that the user grasps the opposite end of the handle and swings the hammer to repeatedly impact the head of a nail or spike to thereby drive the nail as desired. Other such implements include axes, sledge hammers, and the like.
Many implements designed for use in athletic endeavors employ the entirely similar concept of an elongated structure having a working end which is adapted to strike an object, and a handle end which is adapted to be gripped by a user. For example, a racket for use in the game of tennis comprises a hoop-like racket head that is strung with tensioned strings and utilized for striking a tennis ball, and a handle end generally of elongated cylindrical form and wrapped with such suitable pliable material as leather to provide a firm, comfortable and non-slipping grip for the user. Other sports or athletic implements of similar structure in general include squash, racketball, badminton and paddle tennis and deck tennis rackets.
In general, the object of use in any of such implements is to permit a user to strike an object located at some distance from the user's hand to impart a high magnitude of energy, with a high degree of reliable control, to the object being struck.
Sports rackets in particular have evolved in design to permit a user to impart greater force to an object such as a tennis ball by permitting greater racket head speed that could be imparted with prior racket designs. This, however, is not the only, and probably not the most important design criteria for rackets such as tennis rackets. The success of a tennis player in using any given racket depends far more on control of the racket than on maximizing racket hand speed. The wide variety of shots which a tennis player must be able to execute entails wide variations on the application of both power and spin to control the trajectory of the ball with minimum player fatigue resulting. In addition, the player must be able to execute such a variety of shots on both the forehand and backhand side, each of which entails use of entirely different sets of muscles to achieve the objective. Still furthermore, because the player must cover the entire court, perhaps often executing desperation shots or off balance shots, the racket design must facilitate easy manuvering to a variety of orientations including but not limited to frequent repositioning of the racket for different grips by the user for forehand and backhand shots.
The evolution of tennis racket design has seen a wide variety of innovations in racket head size and ocnfiguration, racket weight distribution, frame construction, and the like, all intended to improve player consistency and control by reducing the effects of the impact between the racket head and the ball upon the user's grip. With the elongated handle of the tennis racket, the head of the tennis racket striking the ball not only propels the ball but in addition generates a reaction force which must be supported by the user's body structure through his hand, wrist and arm. The reaction loads must be resisted by the user's hand, wrist and arm if he is to maintain control. It is only with great difficulty and endless training that a player can, without assistance, exercise sufficient control over racket motion to strike the ball with reliable control while maintaining a sufficiently firm grip and wrist to resist all reaction forces generated by the impact. It is said that in tennis everything depends on a firm wrist. This however does not mean an absolutely rigid wrist as the wrist must also be flexible to permit the manuverability necessary for control and to execute the more difficult shots.